The present invention relates to a motorized actuator unit which is suitable to displace a lock lever of a vehicle door latch apparatus between a locked position and an unlocked position.
Conventionally, various actuator units which displace a change-over member between a first position and a second position by motor power. One of them which is closely related to the present invention is shown in FIGS. 15 to 17. This actuator unit A is provided with a cylindrical worm D attached to a motor shaft C of a motor B, and a worm wheel E engaged with the cylindrical worm D (for example, Japanese Patent Laid-Open Publication No. 08-144602 and U.S. Pat. No. 5,564,308). As an example of the change-over member, a lock lever of a vehicle door latch apparatus which is displaced between a locked position and an unlocked position is exemplified.
The actuator unit A of this type includes a cam groove G defined on an top surface of the worm wheel E, and a rotational lever J fixed to an output shaft F and having a contact pin H engaged with the cam groove G for transmitting a rotational force of the worm wheel E to the output shaft F. The worm wheel E is regularly held on a neutral position by a spring force of a return spring (not shown). The cam groove G and the contact pin H also function a clutch mechanism which does not transmit rotation of the rotational lever J to the worm wheel E when the worm wheel E is located on the neutral position. A lock lever K is fixed to an outer end of the output shaft F which projects outside a housing M of the unit.
The conventional actuator unit A has a disadvantage such that moving amount (rotational amount) of the rotational lever J is rather small. The moving amount of the contact pin H of the rotational lever J is subject to a width of the cam groove G which is not longer than a radius of the worm wheel E. In FIG. 15, when the diameter of the worm wheel E is considered to be xe2x80x9c40xe2x80x9d, the width of the cam groove G is about xe2x80x9c12xe2x80x9d and the width of the contact pin H is about xe2x80x9c3xe2x80x9d. Therefore, the moving amount of the contact pin H is about xe2x80x9c9xe2x80x9d which is merely a quarter of the diameter of the worm wheel E, and a rotational angle of the rotational lever J is considered to be aboutxe2x80x9c20 degreesxe2x80x9d. If the worm wheel E and the rotational lever J are coupled each other using a gear teeth coupling, it is possible to set the moving amount of the rotational lever J without depending on the diameter of the worm wheel E, but a function of the clutch mechanism is lost.
Further, the conventional actuator unit A involves a second disadvantage that it is troublesome for coupling the rotational lever J located inside the housing M and a lock lever (output lever) K located outside the housing M. That is, the lock lever K is coupled to the exposed outer end of the output shaft F by using a typical fixing means such as a screw, an adhesive, and a supersonic deposit means or the like.
Further, the conventional actuator unit A involves a third disadvantage that a shape of the housing M is not appropriate. The vehicle door latch apparatus and the actuator unit are mounted in a narrow space of the door or the vehicle body, so it should be formed compact. Especially, the actuator unit A to be mounted on either one of a tailgate (back door/trunk lid) and a cargo room (trunk room) should be formed more compact. FIGS. 16 and 17 show a relation between a door latch apparatus N and a wall assembly P of the tailgate. The wall assembly P is configured by an inner metal panel Q usually facing to the cargo room, and an outer metal panel R facing to the outside of the vehicle. A thickness thereof is about 5 cm. The inner panel Q has a mounting hole T which has a size of a latch body S of the door latch apparatus N. The latch body S is provided with a bracket V to which operation levers W such as an open lever and a lock lever or the like and the actuator unit A are attached.
The door latch apparatus N with the actuator unit A is inserted into an inside space Y of the wall assembly P through a service hole X formed in the inner panel Q, and the latch body S except flanges thereof projects to the outside via the mounting hole T, and then the latch body S is fixed to the inner panel Q by screws or the like. The service hole X is covered by a trim panel Z. Most of the above assembly operation is performed blindly and it is very troublesome.
On the contrary, if the door latch apparatus N is not provided with the actuator unit A, the latch apparatus N is capable of being directly mounted on the mounting hole T by inserting the bracket V and the lever group W into the inner space Y through the mounting hole T, so that the assembly operation becomes very easy. This means that a shape and a size of the conventional actuator unit A are not suitable to pass through the mounting hole T.
An object of the present invention is to provide an actuator unit which is capable of setting a moving amount (rotational amount) of a rotational lever without depending on a radius of a worm wheel.
Another object of the present invention is to provide an actuator unit which is capable of coupling a rotational lever located inside a housing and a lock lever located outside the housing, without using a fixing means such as a screw, an adhesive and a supersonic deposit means.
Further, still another object of the present invention is to provide an actuator unit which has a shape suitable to passing through a mounting hole of a wall assembly.